In [2]:

    

import Pkg
Pkg.add("QuadGK")


    

    




  Updating registry at `~/.julia/registries/General`
  Updating git-repo `https://github.com/JuliaRegistries/General.git`
[1mFetching: [========================================>]  100.0 %.0 % Resolving package versions...
  Updating `/data/.julia-20190315/environments/v1.1/Project.toml`
  [1fd47b50] + QuadGK v2.0.4
  Updating `/data/.julia-20190315/environments/v1.1/Manifest.toml`
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In [ ]:

    

function D(n,x)
using QuadGK
integral, err = quadgk(theta -> 1/pi*sin(n*theta-x*sin(theta)), 0, pi)